Electronic devices are increasingly being developed that are able to bend, flex and twist, such as in wearable electronics. These mechanical requirements present reliability challenges on mechanical components, circuit boards and interconnects, as well as electronic components. In order to limit the stress and strain to these components while still maintaining flexibility, mechanical provisions must be put in place.
Flexible printed circuits (FPC) provide circuit board structures that are less rigid than earlier generation printed circuit boards, and enable varying degrees of flexing, bending and twisting. Flexible interconnects between conductive wires and FPCs are needed for applications where durability and flexibility are a concern.
In conventional structures, an interconnection is made between the conductive wire and the FPCs by first forming a bond pad on a top, outer surface of the FPC and then attaching an end of the conductive wire to the bond pad, typically using solder or conductive adhesive. The bond bad is a continuous layer of conductive material, typically formed as a square or circle. In this manner, the interconnection is made according to a one-to-one structural relationship between the end of the conducive wire and a single bond pad. However, traditional solder and conductive adhesive connections formed in such a structure are rigid and cause stress concentrations.